The wintry weather is the result of a low pressure system moving along the Gulf coast.

Delta is offering customers whose flight plans may be affected by winter weather the opportunity to make one-time changes to their travel schedules without fees. Delta’s weather advisory encourages customers to consider postponing or re-routing their travel to avoid possible inconvenience from expected flight delays.

The airline said customers booked on Delta-ticketed flights to, from or through the following cities may immediately rebook for travel before or after their original travel dates as long as new flights are ticketed and rescheduled travel begins by Dec. 29, 2010:

Atlanta (for travel originally booked for Saturday and Sunday, Dec. 25-26)
Baltimore (for travel originally booked for Sunday and Monday, Dec. 26-27)
Boston (for travel originally booked for Sunday and Monday, Dec. 26-27)
Newark (for travel originally booked for Sunday and Monday, Dec. 26-27)
New York City (for travel originally booked for Sunday and Monday, Dec. 26-27)
Washington, D.C. (for travel originally booked for Sunday and Monday, Dec. 26-27)

Flight delays are possible at these airports as a result of winter weather, and Delta has cancelled flights to minimize delays.

The Air Transport Association was expecting 44.3 million people on U.S. flights between Dec. 16 and Jan. 5 — up 3 percent over the same period a year ago but still below pre-recession travel volume. The average ticket price was $421, up by 5 percent.

The AAA predicted overall holiday travel to rise about 3 percent this year, with more than 92 million people planning to go more than 50 miles by Jan. 2. More than 90 percent said they would be driving.